Ancient Flower Fossil Points to Underwater Origins

The world's oldest known flower never bloomed, but
it has opened scientific questions into whether all
of modern flowering plants share underwater origins.

The newly discovered remains of the oldest, most complete
flowering plant show it lived at least 125 million
years ago, most likely underwater, said University
of Florida (UF) paleobotanist David Dilcher. The discovery
is reported in Friday's issue of the journal Science
and was funded by the National Science Foundation
(NSF).

"This Lower Cretaceous fossil challenges many assumptions
about the origins of flowering plants," said Quentin
Wheeler, director of NSF's division of environmental
biology, which funded the research. "Such fossil discoveries
combine with advances in the analysis of molecular
and morphological evidence from living plants to provide
a classification that is the conceptual framework
for evolutionary biology."

Although it had no petals, there is no question it
was a flowering plant because of the presence of seeds
enclosed in an immature fruit, a trait separating
flowering plants from all other seed plants, he said.

The discovery is important because it provides clues
about how these now-extinct ancestors evolved into
modern living flowering plants, said Dilcher.

"Flowering plants are the dominant vegetation in the
world today," he said. "They're the basic food crop
and fiber source for the world's population. It's
useful for us to understand the relationships among
flowering plants, especially in this day of molecular
genetic manipulations.

"When you sit down in the morning and have a bowl of
Wheaties or cornflakes, that's a flowering plant,"
he said. "When you eat a beef steak, that's from an
animal that ate flowering plants. So, when we study
this fossil, we're looking at the ancestry of what
sustains us in the world today."

The plant was about 20 inches high with thin stems
stretching up in the water to the surface with its
pollen and seed organs extending above the water,
Dilcher said.

The seeds probably dispersed in the water and floated
up along the shore and germinated in shallow water,
he said.

"The mysteries of the origin and radiation of the flowering
plants remain among the greatest dilemmas facing paleontology
and evolutionary biology," said William Crepet, plant
biologist at Cornell University. "This fossil represents
the first evidence of an angiosperm that is basal
to all other angiosperms, yet that does not fit within
any modern taxonomic group of angiosperms - this makes
it one of, if not the most important fossil flowering
plant ever reported."

The fossil was found in China by local farmers who
gave it to one of the paper's coauthors. It is much
more complete than one found at a nearby site four
years ago, which Dilcher also studied, and suggests
origins in water that refreshed the dinosaurs, said
Dilcher.

"After having only a fragment and trying to imagine
what the whole plant was like, it was a great surprise
to find leaves typical of a plant that lived underwater
with characteristics very unique to flowering plants
at such an early age in their history," he said.